Power converters are used to convert alternating current (AC) power to suitable direct current (DC) levels for powering an apparatus, such as laptop computers and other appliances. In portable electronic devices of this sort, it is desirable to maximize power output per topology space.
A power converter requires a resonant element that stores energy so as to set up the oscillations necessary for power conversions. It is very common to employ an inductor as the resonant element to store magnetic energy. Inductors tend to be quite large circuit components and thus place restrictions on the ability of the circuit designer to minimize the overall size of the converter. In addition, inductors are quite "lossy" and therefore have a relative low "Q" value that detracts from the performance of the converter.
In addition, self-oscillating power converters are well known in the art. The most popular are those based on the Royer and Jensen self-oscillating push-pull technology. An inherent disadvantage of these prior art self-oscillating power converters is that they have poor short-circuit and open-circuit load characteristics. In addition, these power converters require special protection and control circuitry.
There is a need for a power converter that optimizes the amount of power that is generated per unit area of the topology, and which uses a resonant element that is more compact and has a higher "Q" than a standard inductor, thus making it more suitable for portable electronic power applications.